Transitional release on the path to desktop/mobile convergence.

Ubuntu 13.04, scheduled for release on April 25, is now available for testing in its second and final beta release. Nicknamed "Raring Ringtail," Ubuntu 13.04 is one of the final releases that's just for desktops and servers. By this time next year, Canonical intends to release a single version of Ubuntu targeting all form factors, including smartphones and tablets.

Ubuntu developers decided to disable a tool that allows easy installation of Ubuntu alongside an existing Windows instance. Wubi, short for Windows-based Ubuntu Installer, lets users install Ubuntu on the same disk partition as a Windows instance. "Due to various bugs in Wubi that have not been addressed in time for this Final Beta, the Ubuntu team will not be releasing the Wubi installer with 13.04," a Raring Ringtail technical overview states. "Combined with the fact that Wubi has not been updated to work with Windows 8, and the focus on mobile client over desktop, the Foundations team does not expect Wubi to be in a releasable state for 13.04."

This doesn't mean users can't dual-boot Windows and Ubuntu. Without Wubi, dual-booting is slightly more complicated to set up and requires separate disk partitions.

One new feature originally planned for 13.04 which didn't make the cut is Smart Scopes. The Smart Scopes aim to enhance the Unity desktop's Dash overlay by providing more data sources to answer users' search queries. The goal is to add many, many scopes, but "[t]he Ubuntu experience would be compromised if all those scopes were running all the time," a wiki page notes. "The goal of the Smart Scopes project is to intelligently decide, for a given query, which scopes are likely to be most relevant to that query so that those scopes can be chosen to be started and return results."

Smart Scopes has been delayed until Ubuntu 13.10, the release in October of this year. "After an extensive amount of work to get the feature ready, unfortunately the dash team doesn’t consider it mature enough for 13.04—it is nearly there, but doesn’t meet the quality needs for Ubuntu," Ubuntu Community Manager Jono Bacon wrote.

One side effect of this decision is that users still have just two choices when it comes to whether the Dash should or shouldn't search the Internet in addition to the local machine. "The loss of Smart Scopes also means that privacy enhancements due in 13.04 to give more granular control over what resources are searched also isn't included and users are left with 12.10's 'all online resources' or 'no online resources' switch," an H-online article states.

Ubuntu 13.04 isn't just about missing features. Unity saw some user interface changes designed to speed up productivity, for example, by making it easier to switch between multiple open windows of the same application, as described by the Ubuntu and Linux news site WebUpd8. "If an application has two or more open windows, users can switch between those open windows by scrolling on the application icon in the Unity Launcher," WebUpd8 states. The Dash has also received performance improvements, and overlay scrollbars.

Raring Ringtail is based on Linux kernel version 3.8.5 and includes both Python 2 and Python 3.3. "We eventually intend to ship only Python 3 with the Ubuntu desktop image, not Python 2," the Raring Ringtail technical overview page says. "If you have your own programs based on Python 2, fear not! Python 2 will continue to be available (as the python package) for the foreseeable future."

13.04 is the midway point in Ubuntu's two-year release cycle. Long Term Support versions are released once every two years and are supported for five years. Additional versions such as 13.04, less stable than Long Term Support ones, are produced every six months. Ubuntu developers have considered ditching the six-month interim releases in favor of "rolling releases" that push new features out more frequently, but no such change has been made as of yet.

Ubuntu did, however, reduce the length of time that interim releases receive support, from 18 months to 9 months. Ubuntu developers also decided to let users "continuously track the development focus of Ubuntu," letting users automatically receive the latest updates to Ubuntu's development releases without having to explicitly upgrade from one version to another. This gives users something like a rolling release if they want to test out the latest updates, which may be unstable.